ok. if anyone is any good at maths (and ask anyone you speak to asap, this is one hell of a plea) how the hell do i do this??:
a stone slides in a straight line across a frozen pond. given that the initial speed of the stone is 5m/s and that it slides 20m before coming to rest, calculate the coefficient of friction between the stone and the surface of the frozen pond.
so, in terms of formulae: u is 5, v is 0, s (distance) is 20m, i figured out acceleration (a) is 0.625 m/s/s and time taken for that is 8s
to find the coefficient, i need to use F=mu x R (mu being the greek letter i don't have a character for on me keyboard)
F being the frictional force, which should be 0 but can't be.
R is the reaction force, which is equal to weight, but from the data given i don't know how to get weight
F=P but i can't figure out P, because i'd need to use F=ma (ie mass (which i don't have) times a, which i have, but it isnt any good on its own)
ARGHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH please help....